It's a rule I have. Every place I spend time should be better because I was there.
Everywhere. A table at Starbucks? I'll wipe it off with a napkin when I sit down, and pick up my mess when I leave.
Be friendly to staff everywhere. Tip great service well. Point out terrible service politely to a manager, because terrible service is bad for everyone (the server, manager, business, and customers are all worse off if terrible service is happening).
Lightly clean any room you go to.
Don't trash a room just because other people are going to clean it.
In really messy, gross environments you're going to be only for a short time, at least don't make it worse.
If you see any hazards on a sidewalk or road that could hurt someone, move them.
In a space that's your own space, spend five minutes per day cleaning it one little area of it. Run a dustcloth or wet paper towel or napkin over one small corner of the room or area.
Maintain your clothing, tools, furnishings, and everything else around you.
If you're living on the road, your bag is your home. Occasionally lightly clean the inside of your pack or suitcase, mend any damage you can fix, throw out junk you've accumulated.
If you're someone's guest, buy/cook more food, groceries, and toiletries, or give them a nice and practical gift, or both.
Wash the dishes if you stay with someone and they've got dishes.
If every space your enter is better after you were there, you become welcome in many more spaces. It's good for your mind. It makes you feel welcome to walk into any area, knowing you're a force for good and you take care of your environment. It gets you into good habits so you treat your own important spaces well. It makes the world a better place.
Constantly improve your environment. Your life will be better if you do.